In prime time television, there are great slots and ones that basically set you up to fail. Overall, the key spot is after most folks are home from work but before they fall asleep. The spot you definitely don't want is 12:30 A.M. on the East Coast (because even for New Yorkers that never sleep that's a bit late).

For some, being offered the opportunity to host a late (late) television talk show would mean the end of a career. But for James Corden, it was pure gold. He introduced a segment known as Carpool Karaoke in which he invited musicians to drive through the streets of Los Angeles with him while singing their most famous songs. With a humorous spin, they also discuss the latest gossip and taboo topics (the guests are in a moving car, so they don't have much choice but to answer). The ratings spoke for themselves.

The now supremely popular show has won numerous awards and been nominated for even more. What was once just an idea he had with George Michael has blossomed into a hit that celebs themselves are clamoring to get onto.

Keep reading for behind the scenes facts and pictures, including how producers turn a car into a film set. You will learn who had the most viewed Carpool Karaoke clip and who Corden liked working with the most. Plus, we'll let you in on the celeb that nearly bailed and the one that actually did.

25 Ariana Grande Catches A Ride To The Set

According to Eternal Lifestyle, celebs that have appeared on Carpool Karaoke and been willing to dish about their experience all agreed on one thing (aside from the fact that James Corden is hysterical): it's all improvised.

Reportedly, the guests only know what songs will be sung (but haven't actually rehearsed with Corden) and nothing else. So, when Ariana Grande was photographed with a bandage on her hand, we had a hunch it wasn't planned.

According to Cosmopolitan, she sustained a cut (no other details) that required medical attention but no stitches. Filming of the segment commenced as though nothing had happened.

24 Selena Gomez Requests A Pit Stop For Fast Food

James Corden doesn't joke about food. So, if you're on his show and you say you're hungry, he is going to make that happen. That's how Selena Gomez found herself in the passenger seat at a fast food drive through.

She was happy with her fries and drink, but Corden wasn't going to let the employee (or her) off the hook that easily. According to Shared, the drink cups had song lyrics written on them and Corden demanded that he receive new cups with Selena's lyrics as a mortified Gomez looked on.

23 Sir Paul McCartney Takes The Crew Abroad

Every once in a while a segment is so good it deserves its own special, as was the case in Carpool Karaoke: When Corden Met McCartney Live from Liverpool.

In the extended version, James and Paul (as in Paul McCartney) drive through Liverpool rather than the typical Los Angeles scene. They sing all of the Beatles classics and take a detour to Abbey Road. According to Thrillist, the duo also surprised people with a concert at a local pub McCartney used to frequent (Corden pretended to be a bartender to throw them off while Paul and the band got set up).

22 Justin Bieber Shields James Corden From His Adoring Fans

James Corden has such a massive following that he needs Justin Bieber to play the role of bodyguard. Okay, that might not be completely true, but both guys did have a good time at least pretending.

According to E News, they did some shopping in the middle of their Carpool Karaoke segment and on their way out of the store they confused the paparazzi by essentially switching roles. Bieber joked that he didn't know how Corden could deal with so much attention all the time.

Back in the car and on camera, it was Bieber's turn to be in the hot seat again as Corden grilled him on his recent photo shoots and the best songs to sing in the shower.

21 Iggy Azalea Says "I Do"

In addition to James Corden's many talents, he is also a wedding planner. Well, not really, but he did offer to help Iggy Azalea find a wedding dress and officiate the big day right after her engagement to NBA star, Nick Young (we're super bummed that didn't work out).

According to Today, Azalea and Corden took a break from singing to try on dresses at a local boutique. They both (yes, both) found ones they liked and got back into the car to reprise some of the Australian rappers most popular songs.

20 Demi Lovato And Nick Jonas Give An Impromptu Concert

Nick Jonas and Demi Lovato are as close as friends come in the business. They've been together through thick and thin, even going on tour together at one point. That doesn't mean, however, they won't take jabs at one another.

During their Carpool Karaoke outing with James Corden, they made fun of each other's past relationships. Eager to change the subject and do more singing than talking, they piled out of the car and performed an impromptu concert on the sidewalk (which quickly drew a crowd). Lacking a real role in the set, according to CBS, Corden grabbed a bucket and some drumsticks to show off his musical talents.

Don't quit your day (errr, night) job, James.

19 James Corden Gets Some Styling Help From Offset

The saying goes something like, "if you believe it, you can be it". While that works for some, it did not work for James Corden when he hung out with Migos and they dressed him in a special wardrobe for Carpool Karaoke.

According to CBS, Quavo picked out a silver jacket and sunglasses for Corden and Offset complimented the style with a gold chain. They suggested that Corden looked like could be in the group. He just needed to believe it and express an attitude of confidence while belting out the lyrics to Migos hits like Motorsport.

Still, no.

18 Cardi B Mixes Things Up At A Senior Center

While Offset was busy making styling decisions for James Corden, Cardi B was putting her own spin on Carpool Karaoke (as Cardi B does). Always being one for inclusion, she insisted that her segment take place at least in part at a senior center (because there is no age limit on fun).

According to Vulture, she and Corden dropped in on a midday session of Mind Body Dance at the Culver City Senior Center. They moved, they grooved, and Cardi B even got hit on by a senior gentleman.

17 Hailee Steinfeld And Millie Bobby Brown Light Up The Green Screen

We have a confession: not everyone gets to be in an actual car for Carpool Karaoke. In the Apple-owned spin-off, celebs are often placed in front of a green screen and made to look like they're cruising down the street.

Young wonders Hailee Steinfeld and Millie Bobby Brown proved in-studio singing can be just as much fun. According to Refinery 29, they also had a good time after the shoot on social media harassing each other over keeping hands on the wheel (which confused a lot of fans that didn't realize they weren't actually driving).

16 Posh Makes A Triumphant Return To Spice Things Up

She came. She saw. She sang. She even played a mannequin and let James Corden carry her around before eventually ending up in a Target window to debut her clothing line.

Victoria Beckham did it all in her Carpool segment, she just didn't mention that the Spice Girls reunion she was hinting at wasn't going to include her (a decision she now feels bad about, according to Billboard).

We'll never forget this, Posh. We'll never forget this. Though, we would be willing to forgive in exchange for a Spice Girls Carpool Karaoke special segment.

15 Adele Breaks Every Carpool Karaoke Record Ever

Producers couldn't believe it when Adele agreed to be on the show (they actually thought it was a joke). She was debuting one chart-topping hit after the next, but was willing to do Carpool?! Not only did she do the show, she broke every record in the process.

According to Metro, she stayed on camera for a whopping three hours. By comparison, most celebs only consent to one hour and that is boiled down to fifteen minutes of footage. Adele's segment went on to become the most watched, amassing nearly 200 million views on YouTube and earning it Thrillist's top ranking.

14 Will Smith And James Corden Roll In With A Marching Band

USC's Spirit of Troy marching band has a packed schedule filled with rehearsals and performances, but they put all that aside for one day when they were presented with the chance to escort Will Smith down the streets of Los Angeles for his grand entrance on Carpool Karaoke.

James Corden and Smith had a little fun with the band on the side, starting songs to see if they could chime in (read: compete) on their instruments. We have to say, and The Tab would agree, the instrumental version of "Gettin' Jiggy Wit It" is pretty catchy.

13 James Corden Is Seriously Afraid To Let Barbra Streisand Drive

James Corden wasn't exaggerating when he covered his eyes and let out a shriek as Barbra Streisand took the wheel, he was truly afraid.

According to Variety, Streisand admitted to him that she failed the driving portion of her license renewal three times. She also told him that she reached out to Tim Cook, CEO of Apple, to have the pronunciation of her last name corrected through Siri. While that anecdote wasn't very comforting and certainly wasn't going to keep her from crashing the car, she did hope it would at least distract Corden.

In the end, Babs (can we call her Babs?) did just fine.

12 Mariah Carey Plays Hard To Get

Mariah Carey gets what Mariah Carey wants. That's it. End of story. So, when she arrived to film her segment of Carpool and refused to sing because she "had a long night" according to Eternal Lifestyle, the crew thought they would have to do without their Christmas special. Luckily, after several hours of convincing, Mariah took her seat in the car and filming went off without any further problems.

It remains to date, according to Today, that the only person to ever actually walk out on Carpool Karaoke was 80s rocker, Bryan Adams.

Close one, Mariah.

11 Filming Pauses On The Boulevard To Review The Plan

Desperate times call for desperate measures. Filming in a car in Los Angeles means sometimes you have to deal with traffic and sometimes you have to pull over entirely to review the plan for the segment (with a six-car convoy not everyone is in the same place at the same time).

Sometimes, according to Variety, all of the above happens when Ed Sheeran is in the car. Sheeran had just finished winning a dare against Corden in which he shoved 55 malt ball chocolate candies into his mouth, so he was a little preoccupied by a sugar rush and didn't mind the stop.

Luckily the talent was patient.

10 Lady Gaga Exposes James Corden To Her Musical Process

James Corden told Lady Gaga to forget she was being filmed for television and to just be herself. It turns out Lady Gaga being herself means embracing her "process", something most musicians and other artists do in some capacity (though it should come as no surprise that Gaga's is a bit extra). Gaga's process involves vocal warmups, deep breathing exercises, and sun salutations. Corden was skeptical, but eventually donned a pink hat to match Gaga's and they sang their hearts out.

Viewers also didn't get to see Gaga's road rage, according to Shared, but everyone can probably use their imagination to picture how that went down.

9 Sound Crews Work Tirelessly To Get The Carpool Karaoke Car Up To Speed

We'd like to take a moment to acknowledge the sound engineers that make Carpool Karaoke possible. It takes a near genius to figure out how to put a camera crew in a moving vehicle without the "crew" part. The result, according to Creative Planet Network, is twelve windshield and headrest mounted cameras that feed seamlessly into an AV system in the back (and produce a hot ride because the sound of the air conditioner interferes with the recording and thus has to be turned off).

And, while we're giving props, let's thank the other drivers. According to Metro, James Corden's car is sandwiched in between five others for safety. Speeds are kept to a minimum and less busy side streets are chosen.

8 Tom Cruise Takes The Show To An Impossible Location

Tom Cruise does his own stunts, even if that means taking over a year to prepare for a skydiving scene. According to People, he performed over 1000 practice jumps for his role in Mission: Impossible - Fallout.

When he was asked onto the Late Late Show, Cruise agreed on the condition that Corden go skydiving with him and they film from the airplane. The result was a very terrified James Corden and a very special Carpool Karaoke that hadn't been done before (cue Mission Impossible theme song).

7 Hailey Bieber And Kendall Jenner Test Their Friendship

In a Carpool spinoff owned by Apple, Carpool Karaoke: The Series pairs celebrities with each other. In the second season, besties Kendall and Hailey gave fans a glimpse into their tight-knit friendship.

According to Entertainment Weekly, the longer version of the segment (some of which was cut) included an intense question and answer period in which Justin Bieber's true thoughts about Jenner were revealed. They took turns picking out songs to play and, as best friends (at least ones that have a secret handshake) would, they loved each other's selections (especially Miley Cyrus and Panic! at the Disco).

6 Bruno Mars Makes (Almost) All Of James Corden's Dreams Come True

According to Eternal Lifestyle, James Corden only brings on guests that he is a huge fan of (and already knows their music by heart). So, how do you choose a favorite among your favorites? Easy. You get Bruno Mars.

Bruno was highly sought after and was the most fun to work with, a self-proclaimed statement by Corden. Bruno will likely remain the favorite unless Corden can land Beyonce, a hope that has been been dashed many times according to Today.